[msan] Intercept shmat.

llvm-svn: 193581

2 files changed, 45 insertions, 0 deletions

diff --git a/compiler-rt/lib/msan/msan_interceptors.cc b/compiler-rt/lib/msan/msan_interceptors.cc
index 842270dca20..0c42e047bad 100644
--- a/compiler-rt/lib/msan/msan_interceptors.cc
+++ b/compiler-rt/lib/msan/msan_interceptors.cc
@@ -1157,6 +1157,22 @@ INTERCEPTOR(int, __cxa_atexit, void (*func)(void *), void *arg,
   return REAL(__cxa_atexit)(MSanAtExitWrapper, r, dso_handle);
 }
 
+DECLARE_REAL(int, shmctl, int shmid, int cmd, void *buf)
+
+INTERCEPTOR(void *, shmat, int shmid, const void *shmaddr, int shmflg) {
+  ENSURE_MSAN_INITED();
+  void *p = REAL(shmat)(shmid, shmaddr, shmflg);
+  if (p != (void *)-1) {
+    __sanitizer_shmid_ds ds;
+    int res = REAL(shmctl)(shmid, shmctl_ipc_stat, &ds);
+    if (!res) {
+      __msan_unpoison(p, ds.shm_segsz);
+    }
+  }
+  return p;
+}
+
+
 struct MSanInterceptorContext {
   bool in_interceptor_scope;
 };
@@ -1459,6 +1475,7 @@ void InitializeInterceptors() {
   INTERCEPT_FUNCTION(pthread_join);
   INTERCEPT_FUNCTION(tzset);
   INTERCEPT_FUNCTION(__cxa_atexit);
+  INTERCEPT_FUNCTION(shmat);
 
   if (REAL(pthread_key_create)(&g_thread_finalize_key, &thread_finalize)) {
     Printf("MemorySanitizer: failed to create thread key\n");
diff --git a/compiler-rt/lib/msan/tests/msan_test.cc b/compiler-rt/lib/msan/tests/msan_test.cc
index e6923828ded..dd9669be052 100644
--- a/compiler-rt/lib/msan/tests/msan_test.cc
+++ b/compiler-rt/lib/msan/tests/msan_test.cc
@@ -1146,6 +1146,34 @@ TEST(MemorySanitizer, shmctl) {
   ASSERT_GT(res, -1);
 }
 
+TEST(MemorySanitizer, shmat) {
+  void *p = mmap(NULL, 4096, PROT_READ | PROT_WRITE,
+                 MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+  ASSERT_NE(MAP_FAILED, p);
+
+  ((char *)p)[10] = *GetPoisoned<U1>();
+  ((char *)p)[4095] = *GetPoisoned<U1>();
+
+  int res = munmap(p, 4096);
+  ASSERT_EQ(0, res);
+
+  int id = shmget(IPC_PRIVATE, 4096, 0644 | IPC_CREAT);
+  ASSERT_GT(id, -1);
+
+  void *q = shmat(id, p, 0);
+  ASSERT_EQ(p, q);
+
+  EXPECT_NOT_POISONED(((char *)q)[0]);
+  EXPECT_NOT_POISONED(((char *)q)[10]);
+  EXPECT_NOT_POISONED(((char *)q)[4095]);
+
+  res = shmdt(q);
+  ASSERT_EQ(0, res);
+
+  res = shmctl(id, IPC_RMID, 0);
+  ASSERT_GT(res, -1);
+}
+
 TEST(MemorySanitizer, random_r) {
   int32_t x;
   char z[64];